Re: degraded RAID array on squeeze

[Milos Negovanovic <milos.negovanovic@gmail.com>]

On Sat, Sep 24, 2011 at 10:50:17AM +0200, martin f krafft wrote:
> also sprach Milos Negovanovic <milos.negovanovic@gmail.com> [2011.09.24.1034 +0200]:
> > one of my servers has experienced degradation in one of its RAID arrays:
> 
> What happened?

I was in the middle of system update via aptitude last week, and it
started giving me strange errors that it cant access /dev/sdb3 ... I
suspect these were errors from underlaying RAID array. At about the same
time smartd sent me a mail stating that the ATA error count has jumped
from 0 to 800 or so.

> 
> > root@micro ~ # mdadm --add /dev/md2 /dev/sdb3
> > mdadm: add new device failed for /dev/sdb3 as 2: Invalid argument
> 
> Does /dev/sdb3 exist?

It exists.

root@micro ~ # cat /proc/partitions 
major minor  #blocks  name

8        0 1465138584 sda
8        1   11717632 sda1
8        2   29296640 sda2
8        3 1424122880 sda3
8       16 1465138584 sdb
8       17   11717632 sdb1
8       18   29296640 sdb2
8       19 1424122880 sdb3
9        0   11716536 md0
9        1   29295544 md1
9        2 1424121720 md2

root@micro ~ # fdisk -l /dev/sdb

Disk /dev/sdb: 1500.3 GB, 1500301910016 bytes
255 heads, 63 sectors/track, 182401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0002ea6d

   Device Boot      Start         End      Blocks   Id  System
   /dev/sdb1               1        1459    11717632   fd  Linux raid
   autodetect
   /dev/sdb2   *        1459        5107    29296640   fd  Linux raid
   autodetect
   /dev/sdb3            5107      182402  1424122880   fd  Linux raid
   autodetect

root@micro ~ # ls -l /dev/sdb3 
brw-rw---- 1 root disk 8, 19 Sep 24 09:21 /dev/sdb3

> 
> > As you can see it fails to re-insert the component! Whats
> > suspicious is that /dev/sdb1 and /dev/sdb2 are just fine in other
> > 2 RAID components, so I don't think that the /dev/sdb drive has
> > failed!
> 
> Sure, it could have partially failed. You need to know what happened
> to be able to figure out what to do now.

I am in dark regarding that, as I said I was in the middle of system
update when I saw first errors.

Regards
-- 
Milos Negovanovic
milos.negovanovic@gmail.com